Electric time delay apparatus



Oct. 8, 1935.

F. W. GODSEY, JR

ELECTRIC TIME DELAY APPARATUS Filed Jan. 26, 1934 Ta :1. l.

J w szszrw a 5/ r 3/ X,3/c d 43 33 Z \V\ m 37 3 53 INVENTOR ORNEY Patented Oct. 8, 1935 UNITED STATES PATENT OFFICE ELECTRIC TIME DELAY APPARATUS Application January 26, 1934, Serial No. 708,388

18 Claims.

This invention relates to an electrical system and apparatus for achieving a cyclic actuation, for example, of a signaling device at and for predetermined time intervals.

One of the objects of this invention is to provide a simple, compact and economical system and apparatus for dependably achieving periodic actuation of, for example, a visual or audible signal and to provide a simple, flexible and thoroughly dependable control of the length of the time-intervals of actuation and of inactivity of such a device. Another object is to provide a system and apparatus of the above-mentionedcharacter capable of achieving in a simple and effective manner the periodic actuation of a control member at precisely predetermined time-in tervals, and in which the time intervals may be relatively altered in a simple, reliable and thoroughly dependable manner, and in which one time interval, for example, that of actuation, may be altered without affecting the other time interval, for example that of inactivity. Another object is to provide a system and apparatus of the above-mentioned character in which successive corresponding periods of actuation, and in which successive cycles of operation are consistently reproduced so that the various corresponding time intervals are identical. Another object of this invention is to provide a system and apparatus of the above-mentioned character that will be of simple, compact and inexpensive construction, eflicient and reliable in operation and well adapted to meet the varying conditions of actual practical use. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combination of elements, and arrangements of parts and in the several steps and relation and order of each of the same to one or more of the others, all as will be illustratively described herein and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which is shown one of the various possible embodiments of the mechanical features of my invention,

Figure l is a representation, partially diagrammatic, of the circuit and apparatus, certain of the latter being shown in front elevation;

Figure 2 is a horizontal sectional view of one of the devices of the system as seen along the line 2--2 of Figure 1, and

Figure 3 illustrates the BI-I curve or flux density-magnetizing force characteristic of a part of the apparatus of Figure 1.

Similar reference characters refer to similar parts throughout the several views in the drawmg.

As conducive to a clearer understanding of certain features of my invention, it may at this point be noted that in the periodic actuation of 5 a controlled member of a signalling system such as, for example, a beacon light or the like, it is necessary, in order that the particular beacon or the like may be readily identified and its location recognized, that periods of actuation or the 10 flash periods of the beacon be of identical duration, and also that the elapsed time-intervals of inaction or periods between flashes be of equal duration. One of the outstanding objects of this invention is to provide a simple, reliable and eco- 15 nomical system and apparatus for achieving precise periods of actuation and inaction of a controlled member; and to provide such a system and apparatus in which the number of moving parts and consequently wear on parts are minimized, 2 and in which the various actions are entirely automatic and dependable, requiring a minimum of inspection or attention. It is further pointed out that in a system and apparatus of the abovementioned character in which a signaling system 25 such as, for example, a beacon light, it is frequently necessary that the period of action and or the period of inaction be changed or set to a new or different value. Another of the outstanding aims of this invention is to provide a system and 30 apparatus in which the periods of action or inaction may be easily changed or altered to give a new or difierent period or relation of periods.

Referring now to the drawing and more particularly to Figure 1, there is diagrammatically 35 indicated at ID a device to be controlled which, for purposes of illustration, may be considered to be a signal or beacon light that is to be cyclically operated, each cycle to include a time-interval of illumination followed by a time-interval of 40 darkness. It may further be assumed that the device I0 is electrically operated or controlled, and therefore has associated with it a circuit in which is included a suitable source of current, conveniently and illustratively taking the form of a storage battery I l, and a circuit-controlling device comprising a fixed contact [2 and a movable switch member [3.

The controlled device, when in the form of a beacon light, is made operative or is flashed on for such a period of time as the electrical circuit is completed through the fixed contact l2 and the movable switch member 13, the resultant circuit being as follows:from one side of the battery ll, conductor l5, movable switch member I3,

fixed contact I2, conductor 4, controlled device I0, and by way of conductor |6 back to the other side of the battery I The signal light is flashed off or is dark during the period of time when the switch |2| 3 is in its open position. The periods of time above referred to may be on the order of two or three seconds, more or less.

The position of the movable switch member |3 with respect to the fixed contact I2 is electromagnetically controlled by a winding H which is arranged, when energized, to bring these contacts into engagement, thus to close the above-described circuit and, when deenergized, to bring the contacts out of engagement, thus to open the above-described circuit.

More specifically, the winding |1 may be constructed in the form of an electromagnet having a suitable core, as indicated, and operates upon a suitably arranged spring-opposed armature; the latter may comprise an armature l8 pivoted as at I9, opposed by the spring 20,.the latter being adjustable. Movable switch member I3 is secured to an insulating rod or bar 2| which in turn is mechanically connected as at 22, to the armature l8.

Accordingly, energization of winding |1 raises the armature I8 and hence closes the abovedescribed circuit at the parts |2-|3 while deenergization of the winding I1 is effective to bring about, under the action of the spring 20, a disengagement of the switch member 3 from the part l2, thus to open the above-described circuit.

The energization of the winding I1 and thus the actuation of the controlled device ID are in turn controlled by a movable switch member and a fixed switch member 25 suitably mounted and insulated as is indicated at 26, being related to mechanism and structure hereinafter described in detail. The circuit of winding |1 extends from a suitable source of current, illustratively a battery 23, conductor 21, movable switch member or contact 24, fixed contact 25, conductor 28, winding |1, conductor 29, and by way of conductor 30 back to the other side of the source or battery 23. Winding I1 is thus energized or deenergized, in this circuit, depending upon the position of movable contact 24.

Next I provide a control for the switch 2425; this includes a core 3|, of iron or the like, of any suitable or appropriate shape, preferably of the shell type, thus forming a closed magnetic circuit and having accordingly an upper horizontal core leg 3| a lower horizontal core leg 3| and vertical and spaced core legs 3| and 3| these core legs may be formed in one piece and of any suitable magnetic material, as will more clearly appear hereinafter.

Adjacent to and mechanically secured to or supported by the core 3|, as by screws 32, is another magnetic core 33, preferably forming a closed magnetic circuit, and hence comprising an upper horizontal core leg 33*, a lower hori zontal core leg 33*, and vertical and spaced core legs 33 and 33 these core legs may be built up or integrally formed in any suitable manner and illustratively and conveniently, for purposes of convenience of construction, the core legs 33 33 and 33 may be made of a single U-shaped piece of iron, the lower ends of the vertical arms or legs 33 and 33 of which receive therebetween the core leg 33 upon which is a winding 34. By this construction the winding 34 and the core leg 33 may be easily assembled to each other and then assembled as a .unit with respect to the U-shaped member 3333 33, thus to form a closed magnetic circuit for the flux of the winding 34.

When the parts 3| and 33 are related to each other as above described, the winding 34 with its immediate core leg 33 extends horizontally across the front of the bottom core leg 3| of the member 3|, the latter having pivoted thereto, as at 35, a lever 36, conveniently in the form of a bell crank lever, whose one arm 3|; extends into engagement with the movable switch contact 24 and whose other arm 36 carries an armature 31 (see also Figure 2) movable toward or away from the left-hand lower end of the core 33, being thus positioned to be within the influence of the fiux in the magnetic circuit of the core 33, though not appreciably affected by any flux traversing the lower core leg 3| Lever 36 and hence armature 31 are biased toward the left by an adjustable spring 38 and by the latter are held against an adjustable stop 39 by means of which the most extreme position of the armature 31 in a direction away from the core 33 may be determined at will. The insulating mounting 26 mounts the insulated switch parts 2425 onto the lower end of the core 3| and holds them in such relation to the lever 36 that the latter may control the engagement or disengagement of movable switch member 24 relative to the fixed member 25; when the spring 38 is made effective or allowed tobecome effective, lever 36 is held in the position shown in Figure 1 and the switch 2425 is open, thus deenergizing winding |1 above-mentioned while actuation of the armature 31 and hence of the lever 36 in clockwise direction about the pivot 35 effects closure of the circuit of winding H at the switch contacts 2425.

If, therefore, the intervals of time during which the armature 31 is permitted to remain in its extreme positions are appropriately controlled, I may correspondingly control the periods of actuation or inactuation of the control device I0.

Through the core 33 I send and maintain permanently a magnetic flux, of fixed direction, thus polarizing the core leg 33; this I may achieve by making the core leg 33 a permanent magnet, though preferably I achieve this polarization by the winding 34 which is connected to be permanently energized by the uni-directional source of energy 23.

v Winding 34 is connected to the source 23 by way of the following circuit:frorn source 23, conductor 21, conductor 40, winding 34, conductor 4|, and by way of conductor 30 back to the other side of the source 23. Thus, winding 34 makes efiective in the magnetic circuit 33 a fixed value of flux, resulting from the fixed number of ampere turns furnished for that purpose by the winding 34 and the steady or fixed current fiowing therethrough from the source 23. This fixed flux, constant in direction, passes through its own magnetic circuit, namely, the core 33, and is substantially confined to that core; it is, however, as above already indicated, available for coaction with the armature 31, related to the winding 34 and its core, so as to be within the range of the fiux in the latter.

However, about both cores 3|33, is a winding generally indicated by the reference character 42; it may be wound or positioned upon the two cores 3|33 in any suitable manner and illustratively it may be wound in two sections, each on one of the vertical legs of the composite core 3| -33. Its terminals or ends are indicated at 43 and 44a. Through the winding 42 or any fraction or fractions thereof is passed a current from the uni-directional source 23, the current being reversed periodically in a manner hereinafter described and for coaction with features more in detail set out hereinafter. The current through the Winding 42 is controlled by switching mechanism which in turn is controlled by the magnetic flux of the structure 3334 and most conveniently this switching mechanism is controlled by the winding above described which, as already pointed out, is controlled by the armature 31 and its switch 24-25. This switching mechanism is arranged so that in one position the current from the source 23 is sent through the winding 42 in one direction and in its other position the current is sent through the winding 42 in reversed direction. The mechanism may be of any suitable construction and illustratively may take the form of two movable switch members 44 and 45, connected to the insulating member 2|, so as to be controlled by the winding l1; movable switch member 44 coacts with fixed contacts 46 and 48, and movable switch member 45 coacts with fixed contacts 4'! and 49. In Figure 1, the switch members 4445 are shown in lowermost position and hence in circuitclosing relation to fixed contacts 46 and 4?, respectively. In this relation the winding 42 about the two cores 3|--33 is connected to the unidirectional source 23 by way of a circuit which may be traced as follows:from source 23, conductor 50, movable switch member 44, fixed contact 46, conductor 5|, movable contact or tap 52 related to the winding 42, sections 42 and 42 of winding 42, terminal 43, conductor 53, conductor 54, fixed contact 41, movable switch member 45, and by way of conductor 55 back to the other side of the source 23; this circuit will hereinafter be termed circuit A.

Movable tap or contact 52 is so related to the winding 42 that any desired fraction or the whole of the winding 42 may be included in the abovedescribed circuit and in the position above as sumed, such a fraction of the winding 42 as is represented by the sections 42=*42 is included in the circuit.

When the movable switch members 4445 are moved upwardly under the control of winding I! so as to break the above-described circuits at the contacts 464l, respectively, and to come into engagement with contacts 4849, respectively, the winding 42 is again connected to the unidirectional source 23 but now in a manner to send the current through the winding 42 (or any desired fraction of the winding) ina direction reversed from its direction of flow when the aboveoutlined circuit is closed.

This new circuit will be seen to extend from one side of source 23, conductor 50, movable switch member 44, fixed contact 48, conductor 56, conductor 54, conductor 53, terminal 43, section 42 of winding 42, movable contact or tap 51, conductor 58, fixed contact 49, movable switch member 45, and thence by way of conductor 55 back to the other side of the source 23; this circuit will hereafter be termed circuit B. Tap or contact 51 is so related to the Winding 42 that any desired fraction or the whole of the latter may be by it included in this new circuit.

Thus, successive reversals of direction of flux produced by the winding 42 may be achieved and these successive reversals bring about certain unique coactions with and influences upon the system and apparatus. These reversals will be seen to be eife'ctive in two magnetic circuits, independent of each other; the first of these is the core 3| and the second of these is the core 33, the latter having therein the polarizing flux above described and conveniently and illustratively achieved by the winding 34.

Considering first certain actions that take place in the magnetic circuit or core 33, reference may first be made to Figure 3 which represents the hysteresis loop of the iron core 3| this loop is to be understood to be the flux density-field intensity characteristic of the iron core 3| after sufiicient reversal of magnetizing field intensity has been achieved to prevent, upon further reversals, a shifting of the hysteresis loop relative to one of the axes and it is to be noted that the loop is symmetrical with respect to both the horizontal and the vertical axes. The abscissa represent the magnetizing force or magnetic field intensity, the latter being a function of the current flowing through the winding 42, while the ordinates represent the density of magnetic fiux in the core 3| itself.

If the maximum magnetizing force in a positive direction is equivalent to the value 0A, the flux density in the iron core 3| corresponding to this magnetizing force is represented by the value BA. If this magnetizing force is diminished, as by diminishing the current in the winding 42 and bringing it to zero, the fiux density in the core 3| still has a substantial value and is determined by the point at which the hysteresis loop crosses the vertical axis and hence the value is that represented by CO. Thus, though the magnetizing force effective upon the core 3| has been reduced to zero, there is still substantial flux density in the core 3|, represented by the value CO in Figure 3, and that remaining flux density is known as remanent magnetism.

If this remanent magnetism is to be reduced to zero, the magnetizing force or field intensity has to be reversed, as by reversing the direction of fiow of current through the winding 42 and such reversal has to be brought to a magnitude sufficient to produce a reversed magnetizing force equivalent to OE; it is at point E that the lefthand part of the hysteresis loop crosses the axis of field intensity and the value OE of field intensity that is requisite to reduce the flux in the core 3| to zero is called the coercive force".

If the field intensity, in the above-described reversed direction, is now increased beyond the value OE, and to a maximum OF (in the negative direction), the fiux density in the core 3| is represented by the value FG, and if now the current in the winding 42 which brought about this maximum field intensity is reduced to zero, the flux density diminishes along the portion GH of the curve and remains at a value of OH (in the negative direction), representing the remanent magnetism now in the reversed direction.

To remove this remanent magnetism, a coercive force equivalent to the value OK but now in a positive direction, is necessary, and this has to be brought about by way of a reversal in current in the winding 42.

Thus, before the magnetizing force or ampere turns in the winding 42 can be brought to the maximum value BA or GF, the remanent magnetism must in each instance be overcome. This and other actions will be more fully described hereinafter, but it may at this point be noted that the abovedescribed switching mechanism which establishes either circuit A or circuit B abovedescribed, takes part in controlling the direction of the, magnetizing force effective upon core 3| and hence whether such force is in the direction 0A of Figure 3 or in the direction OF.

Disregarding the flux in core 33 produced by winding 42, it should first be noted that the polarizing flux produced by the winding 34 in the magnetic circuit or core 33 is such that it is insuincient to effect movement of the armature 31 in a direction toward the right, as'seen in Figure l, the parts being appropriately adjusted or constructed to bring this about; illustratively, the tension of adjustable spring 38 may be utilized for this purpose, or by way of further example, the adjustable stop 39 may be set to provide an air gap between the core 33 and the armature 31 large enough to prevent actuation of the armature 31 under these conditions. Let it now be assumed that all of the movable parts are in the position shown in Figure 1 and that, therefore, circuit A above described through winding 42 is established. Now windings 42 and 34 are wound in such directions relative to the core 33 that, when circuit A is established, the flux produced in core 33 by the ampere turns of winding 42 flows in the same direction as and is additive to the polarizing flux, namely, the flux of winding 34.

But at the moment that circuit A is established, there is effective in core 3| a remanent magnetism in a negative direction equivalent to OH on Figure 3 and the resultant current flow through winding 42 produces a magnetizing force in a positive direction, assuming ultimately a maximum value of 0A in Figure 3, the magnetizing force having had to reach a value of OK before the remanent magnetism OH has been reduced to zero and having had to be still further increased, by the amount KA, before the maximum flux density, in core 3|, of BA, has been achieved.

But the time rate of rise in this circuit A, during the above-described actions, is very low; the rise or increase in the current through winding 42 is opposed not only by the substantial inductance of the combination of winding 42 and core 33, and by the resistance in the circuit but also due to the remanent magnetism in the iron core 34 itself. The flux due to this remanent magnetism in the core 3| is, as is above made clear, opposed to that produced by the current flowing in circuit A. From the moment that circuit A is closed, the current therethrough and hence through the winding 42 starts to increase the direction OA of Figure 3 and the rate of increase of that current is greatly reduced because the magnetizing force which it produces in core 3| has to overcome and is opposed by the remanent magnetism OH which, as already pointed out, has to be reduced to zero, requiring a coercive force of OK and a corresponding value of current before it is actually reduced to zero; thereafter, magnetization of the core 3| or the production in it of flux density in positive direction, along the portion KB, on the curve, takes place and this is achieved by the further increase in current, by the amount of KA, to the total value of 0A. To achieve all of this, requires considerable periods of time, and during the resultant prolonged interval, the iron in the core 3| has passed through the portion HKB of the hysteresis loop.

At the time the magnetizing force has reached the value 0A in the winding 42, there becomes effective in the magnetic circuit of core 33 ampere turns or magnetizing force proportional to the value OA' of Figure 3 and the resultant flux which winding 42, at this moment, sends through the core 33 to be added to the flux of winding 34, is sufficient now with the flux of winding 34 to draw armature 31 to the right and toward the core leg 33 thus diminishing the air gap between the armature 3'! and core leg 33 (for a purpose later mentioned), and moving movable switch member 24 into contact with contact 25, thus closing the circuit to winding H, which is thus energized, moving switch members I3, 44 and 45 upwardly into and holding them in contact with the contacts I2, 48 and 43, respectively.

At contacts |2-|3 the circuit to the control device is thus closed and the latter enters upon a new interval of actuation. By switch members 44-45 the above-described circuit A has been interrupted, and circuit B through winding 42 is closed.

Upon the interruption of circuit A, the magnetizing force or ampere turns in winding 42 drops to zero, the magnetizing force OA being thus removed; but the flux density in core 3| does not drop to zero but moves. along the portion BC of the hysteresis characteristic and momentarily remains at the value CO, representing now a remanent magnetism in a positive direction.

But the closure of circuit B sends current through the winding 42 in reversed direction and that current tends to increase in the direction CF in Figure 3. But here its rate of rise is opposed first by the remanent magnetism CO which must first be overcome and brought to zero and to bring it to zero the magnetizing force or ampere turns and hence the current has to rise to a value OE, the remanent magnetism diminishing to zero along the portion CE of the characteristic, and it is only after the lapse of that interval of time and after the expenditure of that work that the reversed direction in winding 42 can begin to magnetize the core 3| in reversed direction.

Accordingly, the current in circuit B continues, but slowly, to increase beyond the value OE, producing a flux density in the core 3| that increases in the negative direction along the portion EG of the curve, reaching a maximum value of FG, while the current itself in the winding 42 achieves its maximum value which is a function of the abscissa: OF.

During the transition of the core 3| through the portion BCEG of the characteristic of Figure 3, considerable time has elapsed, as will be clear from what has already been stated above, it being additionally pointed out, however, that the rate of fall of current in circuit A, when that circuit is interrupted, and corresponding to the transition of the core 3| along the portion BC of the characteristic can be made to be and preferably is so low that the flow of current, in reversed direction, through coil 42 as a result of the closure of circuit B is opposed also by the decaying current in winding 42 resulting from the conditions existing when circuit A was interrupted, and thus further delaying the building up of the current in circuit B.

During this prolonged interval of time, corresponding to the transition of the core 3| through the portion BCEG of the characteristic of Figure 3, armature 31 has been held in its actuated position, by the flux of winding 34, and armature 31 is not released and the ampere turns of winding 42, when in the circuit B, have sent sufficient flux through the core 33, but in a direction now opposed to the direction of flow of the flux produced by winding 34, to either completely neutralize the flux of winding 34 or to sufficiently weaken that flux to cause a release of armature 31 and its movement, under the action of spring 38, into the position shown in Figure 1; the parts are so proportioned or adjusted that this takes place when the magnetizing force effective in core 3| has achieved the value OF of Figure 3 and hence when the flux "density is equivalent to the value FG.

The actuation in the above-mentioned direction of armature 31 under the control of the parts as above described now result in opening the circuit of winding I! at the switch 2425, whereupon winding causes switch members I3, 44 and 45 to be moved downwardly, under the action of springZil, thereby interrupting the circuit of the controlled device it] at the contacts |2--|3 and thus terminating a prolonged interval of time, which may be several seconds or more or less, of actuation of the device It, and by way of switch members 43-45 thus interrupts circuit B and establishes circuit A.

But the interruption of circuit B commences a slow decay or fall of the current in winding 42, the fiux density in core 3| falling along the portion GB of the characteristic of Figure 3 to leave in the core 3| a remanent magnetism OH, in the negative direction, which, as well as the above-mentioned slow decay of current in the winding 42, has to be overcome by the current starting to rise in the newly established circuit A,

whence cycle of operation is repeated.

Thus, the time interval during which the switch |2-|3 is open and the time interval during which the switch |2-|3 is closed can be and are made relatively very long, being, as already above indicated, on the order of several seconds or more. Each'cycle, made up of two such successive time intervals and corresponding therefore to a complete cycle of action or inaction of the controlled device I0, are accompanied by the passage of the conditions in the inductance core 3| through the hysteresis loop or characteristic of Figure 3. Each time interval corresponding to a passage of the conditions of the core 3| along the characteristic of Figure 3 from G to B or from B to G is relatively long and its length is contributed to by not only the low time rate of increase of current in circuits A or B, due to the factors of resistance in the circuit and inductance of the combination 423|, to the low time rate of fall of current at the interruption of one circuit to oppose the rising current when the other circuit is established, but also due to the arrangement whereby the current in each circuit must overcome the efiect of the very substantial remanent magnetism that is made to act in a direction to oppose the magnetizing force produced by the increasing current. Such facts as these are furthermore greatly enhanced in effect because the core 3| is preferably made of an iron of high magnetic permeability. During each cycle the current that is to pass through the inductive winding 42 must first oppose and bring to zero a substantial remanent flux in the iron core before it can magnetize the core itself. By such coactions as these, I am enabled to cause an inductance to bring about a vastly lower rate of increase in current therethrough than has heretofore been possible and thus to achieve vastly longer time intervals in the actuation of the device In than has heretofore been possible.

In the foregoing and for simplicity of description, it may be considered to have been assumed that the same fraction of winding 42 or the whole of winding 42 was made to be effective in each of the two circuits A and B, in which case, of course, the two time intervals that make up the cycle of operation of the device ID are substantially equal, it being understood, in that case, that the movable taps or contacts 52 and 5'! are coincident in position or engage the same turn of the winding 42. The length of these equal time periods may be varied by shifting, preferably conjointly, the two taps 525'5 along the winding 42, thereby to include in each circuit the same but a different fraction of the turns of winding 42. If more turns are included, thus increasing the inductive reactance of the combination 3|--42, these time intervals are lengthened and if the number of turns of winding 42 is diminished, the time intervals are shortened.

However, and still assuming equal time intervals, the iron core 3| is always worked through the same hysteresis loop or characteristic, such as that of Figure 3, irrespective of change in the number of turns of winding 42 that are made effective; this because, the eifective portion of winding 42, whether in circuit A or in circuit 3,.

must achieve ultimately the same magnetizing force or ampere-turns to bring about an actuation of the armature 3? which in turn brings about a cessation of one time interval and the commencement of the next.

If, on the other hand, it is desired to make one time interval longer than the other, the taps 52 and El are dissimilarly positioned along the winding 42, for example, as shown in Figure 1, thus to cause a greater number of turns of winding 42 to be included in one circuit than in the other. In Figure 1, for example, portions 42 and 42 of the winding 42 are included in circuit A, giving one value of inductive reactance, while portion 42, smaller than the portions included in circuit A, is included in circuit B, thus giving a smaller value of inductive reactance. In such case, the time interval is longer when circuit A is eifective than the time interval when circuit B is effective; if the device l0 were to represent a flashing lamp, the interval of darkness is thus made longer than the interval of lamp illumination. Here, again, though there is now dissimilarity in the turns of winding 42 respectively included in circuits A and B, the iron of core 3| is nevertheless Worked through the same hysteresis loop or characteristic, such as that of Figure 3, for in each case (circuit A and circuit B) the same magnetizing force or ampereturns must be achieved before one time interval is terminated and the next commenced.

For example, if the turns represented by the portions 42 and 42 of winding 42 included in circuit A are twice the number of the turns of portion 42 included in circuit B, the ultimate magnetizing force or ampere-turns achieved thereby will be the same, as above pointed out, to bring about actuation of the armature 31 and switch 2425, though the current effective in circuit B, and hence in portion 42 of the inductance 42, will be twice the value of current effective in circuit A and hence in portions 42 and 42 thereby achieving equality of ampereturns or magnetomotive force. And in each instance and because of the achievement of the same ampere-turns or magnetizing force and hence because the core 3| is caused to pass through the same hysteresis characteristic (Figure 3) the remanent magnetism left effective at the interruption of one circuit to be overcome, as above explained, upon the closure of the other circuit, will be the same, and hence the coercive force necessary to overcome the remanent magnetism will be the same in each circuit. This feature of action is important in that it achieves dependable independence of adjustment or setting of the value of one time interval of a cycle of operation of the device ID with respect to the other time interval.

For example, if it is desired to change the length of the time interval during which circuit B is effective and not to change the length of the time interval during which circuit A is effective, tap or contact 52 (in circuit 'A) is not shifted, thereby not changing the number of turns of winding 42 to be efiective in circuit B; such action has no reflex action, and the time interval of circuit A remains the same and is unaffected by the new time interval efiective in circuit B, and vice versa; this because the same ultimate magnetomotive force, or ampere-turns, or magnetizing force, is achieved in each instance, and the cessation of action of one circuit leaves the core 3| with the same amount or value of remanent magnetism to be overcome by and in the other circuit when that is made efiective.

Thus, I achieve ease and convenience and precision of determination of the relative lengths of the time intervals of a cycle of operation of the device It] and particularly where the latter is in the form of a beacon light, or the like, whose identification is achieved by measuring the lengths of intervals of darkness and of light, I am enabled to achieve a wide range of difierently related time intervals with speed, accuracy and precision.

I have above mentioned that the rising current in one circuit may be opposed by the falling current resulting upon the breaking of the other circuit. This effect I greatly enhance by bridging across the terminals 43-44 of the inductance 42 a. gaseous discharge tube 60, as by conductors 6| and 6253; this tube may be of any suitable construction and illustratively it may comprise any suitable container having therein suitably spaced discharge electrodes and containing an atmosphere of a suitable gas, such as neon, at a suitable pressure, such as several millimeters. It may be constructed, in any suitable manner as is now well known in the art, to have a breakdown voltage on the order of or volts where the inductance 42-3l is of such a character that the decay of current therein, when its circuit is interrupted, gives rise to a voltage therein on the order of 1000 volts or so.

In operation, when circuit A or circuit B is interrupted, thus to start collapsing the magnetic field of windings 42 and thus to start this decay of current therein, the energy resulting from the latter is shunted away from the switch contacts 4B4841-49 and related switch members, and is now to be dissipated by and in the gaseous discharge tube 60; gaseous conduction takes place from electrode to electrode in the device 60 but conduction therethrough and hence the dissipation of the energy in the winding 42 corresponding to this collapsing magnetic field or due to the decaying current therein, takes place at a limited or controlled rate, due to the action of the device 60, thus delaying the rate of fall or decay of the decaying current and this I may achieve to such an extent that, when the next circuit (either A or B) is made effective, the current therein and tending to flow in opposition to the direction of this decaying current is of a large enough value to oppose the current flow in the newly es- 5 tablished circuit or, viewed in another light, sets up a back E. M. F. in this newly established circuit that still further delays the rise of current from the source 23 in the newly established circuit. Thus, I am enabled still further to increase 10 the length of the time intervals. The device 60 also safeguards the above-mentioned switch contacts against sparking for its breakdown voltage is much less than the breakdown voltage of the air gaps at these contacts, 15 and thus this stored energy seeks out the tube 60 as the path of lesser resistance and it is through the tube 60 that the discharge takes place. Moreover, the tube 60 has the characteristic that its resistance, after discharge therethrough has been 20.

commenced is less than would be or is the resistance of the spark discharge path that would otherwise be formed at these switch contacts; through such an arc, the dissipation of this stored ene gy would be exceedingly rapid, being of high 25 resistance, but through the once established discharge through the device 60, the dissipation of this stored energy takes place at a much slower rate because of the lower resistance of the device 60' as compared to the resistance of the spark. 80

The breakdown voltage of the discharge device 60 is, moreover, in excess of the voltage of the source 23 and is such that the battery or source 23 is incapable of sustaining the discharge in the device 60 upon the closure of either circuit 35 A or circuit B; the discharge in the device 60 therefore ceases as soon as the decaying current (or its voltage) has diminished to a value insurficient to maintain the discharge.

Thus, aside from the achievement or delay in 40 the rise in current by such coactions as have above been described in connection with the hysteresis characteristic of Figure 3, I am enabled to cause the energy stored in the winding 42 or in the magnetic field ultimately achieved by the latter in the 45 core 3| at points B or G of Figure 3 to coact to achieve still further prolongations oi the time intervals that it takes the current in the winding 42, in either circuit A or B, to achieve the intended or desired maximum magn zing flux. 50

In the circuit or switch 24-25 is inserted a condenser 10 (Figure 1) related thereto and to the circuit of winding I! as indicated in Figure 1; in series with the condenser 10 is a resistance 1 I. These parts are inserted to protect the con- 65 tacts 24-25 and in practice the condenser I0 takes the form of an electrolytic condenser which may be embodied in relatively small cubical volume of adequately high capacity for the relatively low voltage involved and when so embodied it 0" has the inherent characteristic of providing an equivalent series resistance, indicated by the resistance 1 I, thereby making it unnecessary to provide a separate external resistor unit. With this arrangement, the lives of the switch contacts 24--25 are greatly prolonged.

It will thus be seen that there have been provided in this invention a system and apparatus .in which the various objects hereinabove pointed out, together with many thoroughly practical and 70 unique advantages are successfully achieved. It will be seen that the apparatus is of a thoroughly practical character, is capable of dependably achieving cyclic actuation in which the periods that make up any cycle may be reliably deter- 7 mined, made equal, or made different, and that these actions. may be achieved without causing the setting of one time interval or period of a cycle to disturb or influence the length of the other period or time interval.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In apparatus of the character described, in combination, a source of direct current, a fluxresponsive control member movable into either of twopositions,and meansforcontrolling the lengths of the time intervals during which said member occupies said positions, said means including magnetic-fiuX-producing means, said member being exposed to the flux thereof, an iron core, a winding about the latter and capable, when energized, to magnetize said core, and said core being capable, when said winding is deenergized,

of retaining residual magnetism, said winding being positioned to affect the flux of said fluxproducing means, and means for sending current through said winding from said source in a direction to overcome the residual magnetism in said core.

2. In apparatus of v the character described, in combination, a source of direct current, a fluxresponsive control member movable into either a of two positions, and means for controlling the lengths of the time intervals during which said member occupies said positions, said means including magnetic-fluX-producing means, said member being exposed to the flux thereof, an iron core, a winding about said core and capable, when energized, to magnetize said core, and said core being capable, when said winding is deenergized, of retaining residual magnetism, means for sending current from said source through said winding in a direction to overcome the residual magnetism of said core, and means whereby current flowing in the circuit of said winding and source affects the flux of said flux-producing means, thereby to afiect the position of said member, said last-mentioned means comprising means causing flux from said winding to affect the flux of said flux-producing means.

3. In apparatus of the character described, in combination, a source of current, a movable member capable of assuming either of two positions, two adjacent magnetic circuits, means for producing a flux in one of said circuits, means controlled by flux in said one circuit for controlling the position of said member, a winding for setting up flux in both of said circuits and capable, when energized, to magnetize said other magnetic circuit, and said other magnetic circuit being capable, when said winding is deenergized, of retaining residual magnetism, and switching means controlled by said movable member for directing current through said winding from said source in a direction to oppose the residual magnetism in the other of said magnetic circuits.

4. In apparatus of the character described, in combination, a source of current, a movable member capable of assuming either of two positions. two adjacent magnetic circuits, means for producing a flux in one of said circuits, means controlled by flux in said one circuit for controlling the position of said member, a winding for setting up flux in both of said circuits, means for changing the inductive reactance of the inductance formed by said Winding and the other of said magnetic circuits, and means controlled in response to the flux in said one magnetic circuit for reversing the direction of current flow from said source through said winding.

5. In apparatus of the character described, in combination, a source of current, a movable member capable of assuming either of two positions, two adjacent magnetic circuits, means for producing a flux in one of said circuits, means controlled by flux in said one circuit for controlling the position of said member, a winding for setting up flux in both of said circuits, switching means interposed between said winding sa'd source for reversing the direction of current flow through said winding, means for varying the number of turns of said winding through which current from said source is to pass, and means actuating said switching means in response to change in position of said movable member.

6. In apparatus of the character described, in combination, a source of current, a movable member capable of assuming either of two positions, two adjacent magnetic circuits, means for producing a flux in one of said circuits, means controlled by flux in said one circuit for controlling the position of said member, a winding for setting up flux in both of said circuits, switching means interposed between said winding and said source for reversing the direction of current flow through said winding, there being more turns of said winding effective when current from said source flows therethrough in one direction than there are eifective when the current is reversed, and means responsive to said movable member for controlling said switching means.

7. In apparatus of the character described, in combination, a source of current, a movable member capable of assuming either of two positions, two adjacent magnetic circuits, means for producing a flux in one of said circuits, means controlled by flux in said one circuit for controlling the position of said member, a winding for setting up flux in both of said circuits, switching means interposed between said winding and said source for reversing the direction of current flow through said winding, means operable at will for determining how many turns of said winding shall be effective when current flows therethrough in one direction as compared to the turns to be efiective when the current is reversed, and means operating said switching means in response to change in position of said movable member.

8. In an inductive time delay apparatus having a winding about a core and reversing-switch means eiTective upon said winding, the combination therewith of means having a lower breakdown voltage than the contacts of said switch means but a higher resistance after breakdown than the resistance of said switch means after spark-over, shunted about. said winding for retarding the dissipation of the energy generated in said winding upon the collapse of the magnetic field of said core.

9. An apparatus like that of claim 8 in which the shunted means comprises an electric conduction device.

10. An apparatus like that of claim 8 in which the shunted means is a gaseous discharge device.

11. An apparatus for achieving electrically successive long time intervals, comprising, in

combination, reversing-switchmeans, a polarized relay for controlling the latter, said polarized relay including a member of magnetic material, an iron core, a winding thereon and a source of current in circuit therewith and said reversingswitch means, and means for affecting said polarized relay by current under the control of said reversing switch means comprising means mounting said member in a position to be affected by the flux produced by said winding.

12. An apparatus for achieving electrically successive long time intervals, comprising, in combination, reversing-switch means, a polarized relay for controlling the latter, said polarized relay including a'core of magnetic material, an iron core, a winding thereon and a source of current in circuit therewith and said reversing-switch means, and means subjecting said core of said polarized relay to flux of said winding produced by the reversing current controlled by said switch means.

13. An apparatus for achieving electrically successive long time intervals, comprising, in combination, reversing-switch means, a polarized relay for controlling the latter, an iron core, a Winding thereon and a source of current in circuit therewith and said reversing-switch means, and means subjecting said polarized relay to flux produced by said winding.

14. An apparatus for achieving electrically successive long time intervals, comprising, in combination, reversing-switch means, a polarized relay for controlling the latter, said polarized relay having a core of magnetic material, a second core of magnetic material, a source of current, and a winding common to both of said cores, said winding being in circuit with said source and said reversing-switch means, whereby said polarized relay is subjected to flux produced by the reversing current controlled by said switch means.

15. An apparatus for achieving electrically successive long time intervals, comprising, in combination, reversing-switch means, a relay for controlling the latter, said relay having a core, a source of current, a winding on said core unidirectionally energized from said source for thereby polarizing said relay, a second core, a winding on said second core connected to said source through said reversing-switch means, and means for afiecting said polarized relay by current under the control of said reversing-switch means.

16. An apparatus for achieving electrically successive long time intervals, comprising, in combination, reversing-switch means, a relay for controlling the latter, said relay having a core, a source of current, a winding on said core unidirectionally energized from said source for thereby polarizing said relay, a second core. a winding on said second core connected to said source through said reversing-switch means, and means subjecting said polarized relay to flux produced by the reversing current controlled by said switch means.

17. An apparatus for achieving electrically successive long time intervals, comprising, in combination, reversing-switch means, a relay for controlling the latter, said relay having a core, a source of current, a winding on said core uni-directionally energized from said source for thereby polarizing said relay, a second core, and a winding extending about both of said cores and connected in circuit with said source but through said reversing-switch means, whereby said polarized relay is subjected to flux produced by the reversing current in said secondmentioned winding.

18. An apparatus for achieving electrically successive long time intervals, comprising, in combination, reversing-switch means, a relay for controlling the latter, said relay having a core, a source of current, a winding on said core unidirectionally energized from said source for thereby polarizing said relay, a second core, said two cores forming individual and closed magnetic circuits, and a winding about both of said cores and thereby affecting both of said closed magnetic circuits and connected through said reversing-switch means to said source, whereby said relay is afiected by flux produced by the reversing current in said second-mentioned winding.

FRANK W. GODSEY. JR. 

